1. Field of the Invention
The present invention generally relates to a combined processing apparatus, which can perform a punching process while bending a hollow material as a workpiece.
2. Description of the Related Art
FIGS. 5A to 5C are views which explain a bending process and a punching process of an extruded material in accordance with a conventional method, which generally comprises the following steps for bending and punching a workpiece. FIGS. 5A and 5B show principles of a conventional typical bender.
In FIG. 5A, a bender 100 is provided with a metal mold 101, a fixed chuck 102 and a movable chuck 103. A hollow material as a workpiece 104 is clamped by the fixed chuck 102 and the movable chuck 103. The movable chuck 103 applies a tension to the hollow material 104 in a direction of arrow (1).
FIG. 5B shows a bending process which is performed by moving the movable chuck 103 in a direction toward the metal mold 101 as shown in arrow (2), while applying a tension to the hollow material 104 by means of the movable chuck 103,; thereby, pressing the hollow material 104 to a curved surface 105 of the metal mold 101.
FIG. 5C shows a punching process, which is performed by punching holes 108 and 109 in the bent hollow material 104 by means of drills 106 and 107 of a drilling machine.
However, in the above conventional embodiment, it is necessary to take off the workpiece from the bending machine and set the workpiece to the drilling machine. Accordingly, since the above conventional embodiment requires two steps for processing, there is a problem that the time necessary for processing gets extended thereby, increasing the cost for processing.
FIGS. 6A, 6B, 6C and 6D show several kinds of cross sections of a conventional workpiece. When various kinds of small parts are attached to the workpiece or the workpiece is attached to the other member by a bolt or the like, it is necessary to punch the workpiece so as to insert the bolt or the like or to attach a clip thereto. Concrete examples thereof will be explained below.
FIG. 6A shows an example in which a workpiece 111 having a channel shape is mounted on a die 112 and a hole 114 is punched by a punch 113. Reference numeral 115 denotes a punching scrap.
FIG. 6B shows an example in which a hole 124 is punched in a workpiece 121 having a rectangular cross section by a punch 123. Reference numeral 125 denotes a punched scrap. In a case in which the workpiece 121 is a light alloy extruded material (such as, an aluminum alloy or the like), since a rigidity is small, a punched surface is curved downward as shown and it is necessary to correct this curved deformation so that a number of the processing step is increased and a cost for processing is increased. Accordingly, it is necessary to form the workpiece 111 into a channel shape as shown in FIG. 6A, thereby directly receiving the surface to be punched by the die 112. Otherwise, as shown in FIG. 5C mentioned above, it is necessary to punch by the drills 106 and 107. Because the drills 106 and 107 give less effect to the hollow material 104 as a workpiece than the punch 123.
FIGS. 6C and 6D show examples in which a clip 133 having an inverted-T cross section is attached to a workpiece 133 with a recessed groove 131. If an extrude molding is employed, the recessed groove 131 can be integrally formed with ease so that it is not necessary to punch the workpiece 132.
However, as is apparent from FIGS. 6A and 6B, if the workpiece has a rectangular cross section, there is no way to form a hole without punching by the drills so that the hole is limited to a circular hole.
Further, the examples of FIGS. 6C and 6D have a problem that the weight is increased at a degree of the recessed groove 131 so that the cost for material is increased and the total weight of the structure is increased.